Quick Reaction Foils Kidnap Attempt : Crime: Three men drag a 2-year-old girl into a car and then release her unharmed after being chased by a man who thought the child was his.

It’s the best mistake that Art Casas ever made, no mistake about that.

When Casas heard neighbors shout that a child was being kidnaped, he thought they meant his 5-year-old son. So he jumped in his pickup and chased after the old station wagon that was disappearing down South Shipman Avenue in La Puente.

But it turned out that little Johnny Casas was not the one whom three men had grabbed Thursday night from the sidewalk next to Northam Elementary School.

By the time Casas caught up with the fleeing station wagon a few blocks away, two of the men had jumped out and run away. The victim--who was released unharmed--turned out to be a 2-year-old girl.

Los Angeles County sheriff’s investigators said the 2-year-old was unhurt in the brief abduction. They declined to identify her or her parents.

Deputies said the toddler was with several other children playing on the sidewalk when the station wagon pulled up and one of the men commented on how cute she was. After failing to coax the girl into his arms, the man grabbed her.

Casas, who was across the street at his sister-in-law’s house, heard the youngsters’ screams. He glanced up and down the street for his son, and when he did not see him, feared the worst.

When the kidnapers saw Casas jump in his truck to chase them, they pulled over about a block away. The girl was released and two men fled. Then the third man sped off with Casas closing in from behind.

According to Casas, he feared that his son was still in the station wagon when he raced in front of it and forced it to the curb near Valley Boulevard. After discovering that the boy was not inside, he made note of the man’s description and the station wagon’s license number and turned around to hunt for the other two men.

“I couldn’t wait for the police,” the 36-year-old mechanic said. “I thought they had my boy.”

In the end, Casas learned that his son was safe: his mother-in-law had given Johnny permission to go for a walk with some neighbors.

In fact, the boy had been unaware of the neighborhood drama “until he saw his dad drive by real fast” chasing the kidnapers, said his mother, Dolores Casas. At home a few blocks away, she had rushed to her sister’s house after neighbors telephoned with the erroneous news that Johnny had been abducted.

“When I saw my boy walk in, I passed out,” said Dolores Casas, 32. “I’d been so frightened.”

The girls’ parents have thanked him for his role, Casas said, and sheriff’s deputies Friday were praising him as a good Samaritan. On Friday evening, deputies were continuing to search for the station wagon and the driver, described as Latino, between 28 and 34 years old, about 5 feet, 8 inches tall and about 170 pounds. The station wagon was described as a brown 1980-85 Chevrolet, possibly with license number 2GLR280.